Elizalde P V, Guerra F K, Gravano M, Lanari C, Lippman M E, Charreau E H, Lupu R
Instituto de Biología y Medicina Experimental (IBYME) Obligado 2490, Buenos Aires, Argentina.
Cancer Invest. 1995;13(2):173-80. doi: 10.3109/07357909509011687.
We investigated the expression of transforming growth factors beta 1 and alpha (TGF-beta 1, TGF-alpha) in hormone-responsive (MPA-R) and unresponsive (MPA-U) tumor lines obtained from medroxyprogesterone acetate (MPA)-induced mammary adenocarcinomas in BALB/c mice. The tumors were transplanted into MPA-treated and untreated mice. TGF-beta 1 gene expression was observed in the MPA-R lines growing in untreated animals, but not in MPA-treated mice. TGF-beta 1 mRNA was not detected in the MPA-U tumor lines growing in either MPA-treated or untreated animals. In MPA-R lines the levels of TGF-beta 1 expression were inversely correlated to growth rate. High-affinity TGF-beta 1 receptors were present in the MPA-R tumors. These results suggest that one of the mechanisms by which MPA exerts its proliferative effect on MPA-R tumor lines is inhibition of the expression of TGF-beta 1. Thus, the lack of expression of TGF-beta 1 in MPA-U tumors may be related to the acquisition of autonomous growth.
我们研究了从醋酸甲羟孕酮（MPA）诱导的BALB/c小鼠乳腺腺癌中获得的激素反应性（MPA-R）和无反应性（MPA-U）肿瘤细胞系中转化生长因子β1和α（TGF-β1、TGF-α）的表达。将肿瘤移植到经MPA处理和未处理的小鼠体内。在未处理动物体内生长的MPA-R细胞系中观察到TGF-β1基因表达，但在经MPA处理的小鼠中未观察到。在经MPA处理或未处理的动物体内生长的MPA-U肿瘤细胞系中均未检测到TGF-β1 mRNA。在MPA-R细胞系中，TGF-β1表达水平与生长速率呈负相关。MPA-R肿瘤中存在高亲和力TGF-β1受体。这些结果表明，MPA对MPA-R肿瘤细胞系发挥增殖作用的机制之一是抑制TGF-β1的表达。因此，MPA-U肿瘤中TGF-β1表达的缺失可能与自主生长的获得有关。
